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bad noise....

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Well, disaster has struck. I was showing off a little in the centre of Town yesterday and booted it off the lights slightly more than I intended, revs went slightly over 6000rpm and then there was a clatter / tapping suddenly, which changes speed with engine speed and also makes a noise when cranking the engine over - The AA recovered me and it is heading to Moorland Jones tomorrow as my local garage... any ideas and other than kicking myself for revving it a little more than usual, should it have been ok over 6000? It does have high lift cams and had a head rebuild when I first got it, about ten months ago...? Any ideas on what it could be - I dont think it is exhaust as it makes the noise when cranking the engine. :(

To add to that, the AA chappie felt it was a head related issue (sounded like it).. any ideas?

Edited by skiing

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Thats no good. :( Hopefully it isn't terminal.

Here is a couple of guesses.

If the engine runs normal with the exception of the loud tapping it might have spit out the valve adjusting shim.

If the engine runs rough along with the loud tap the valve might have made contact with the piston and is now bent.

Best of luck,

Jeff

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Henry,

Start by checking TDC for static timing. You may have jumped a tooth on the timing belt. Next, if you have access to a 150 psi air compressor and a leakdown tester, do that. If you munched a valve, either exhaust or intake, you will know immediately. Have to open the throttles to listen for air on the intake side. Rather that than starting it and possibly doing more damage. if you're losing air and there is no noise at the tailpipe or carbs, don't forget to check the crankcase breather tube. May Anthony Colin Bruce smile upon you in your time of need!

Lyn

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Well apparently on first listen, the garage feel that it not a head issue and is a big problem... Subject to usual tests tomorrow. So if ut is engine rebuild time, what options should I pursue? Go high compression? I would like the power of a turbo from an na, so I might as well bite the bullet now.. Any suggestions o how I get that power? Hc engine, port and polish? Stainless exhaust?

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How much do you want to spend...?

There is a good guide on the Lotusbits website: http://www.lotusbits.com/improving_your_lotus.pdf (check out the second half of the document). I would recommend speaking to Mike about the process.

To uprate an LC engine to HC spec you are going to need to look at changing the pistons/liners, gas flowing the head and uprating the cams. If you want to fit proper HC pistons & liners you will have to get the block altered to fit them, as the HC liners have a slightly larger diameter, though there are other possible options available that have been discussed here.

I looked at the process quite a bit as I wanted to do the same to my old car, and eventually came to the conclusion that the most cost effective way to go about things would probably be to start with an actual HC engine, which gives you the pistons and liners, a gas flowed head (though this can be further improved…) and an up-rated inlet cam. It also has some better cooling mods, the round toothed cam belt and the improved cam towers.

Lotusbits (and I am sure some of the other suppliers) will probably be able to sell you an HC engine, but I noticed there is one for sale on eBay at the moment. There is also a gas-flowed head for sale too.

From there you need a much better full exhaust system (again I would check out the one from Lotusbits...) and some changes to your carbs. You should nudging 200bhp by then!

My car has the following: HC engine block/pistons/liners, gas flowed LC head, L14 cams, vernier pulleys, electronic fuel injection, 4-2-1 manifold, free-flow exhaust system & a K&N filter. When I had the ECU re-mapped a few weeks ago it made 175bhp at the wheels, which would give the engine an estimated power at the fly of around 210bhp. :D

Scott

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I thought as much re. the HC engine - think this seems the best approach - the annoying thing is I had the head rebuilt only recently and it has high lift cam shafts and modifications. I also already have 48 carbs (rather than the normal 45s) so should be able to get more power - think I will need a better exhaust though as mine looks pretty original. Interesting to see that you combined the original LC head with the HC lower engine - do you have any cooling modifications? and is it fast!? :thumbsup:

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Did you fit new steel cam followers when you put in the high lift cams...!!!!!! I think you know where i'm going with this...!!! Talk to mike6 and compare knocking noises,...

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My money is on the timing belt jumping teeth, and some bent valves...especially with high lift cams. Hopefully nothing too bad....

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Dave (CHANGES) suggested you have a word with me - see my thread on Stevens Esprit - loud ticking noise. As soon as I lifted the cam housing top it was evident that an exhaust cam follower had shattered and damage has been done to the cam, cam housing and valve end as well as valve spring retainer. A top end strip down is now in progress but taking my time it seems possible with engine in situ. Hopefully damage has not been sustained to the piston crowns

Let me know if you want any help as I am doing this as we speak using Daves very valuable experience and help. I still bear the cuts and scratches on my arm !!

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Interesting to see that you combined the original LC head with the HC lower engine - do you have any cooling modifications? and is it fast!? :thumbsup:

I bought the car with the engine already like it is (though I have changed the exhaust) so I don't really know why it has a LC head or if it has any cooling mods - have not had any problems yet though.... I looked into all the modifications for my old car, but then went and parked it in a field (see the blog posts for "death of an esprit"!). When I started to look for a replacement I found my current car for sale with all the modifications already done (plus a much needed PNM brake upgrade, and a re-trimmed interior). Steve Greenauld re-built the engine and sold it to the previous owner who had it fitted to the car.

It is a lot quicker (and more torquey) than my old car - which had a very well set-up standard engine... :yes:

I have just bought a set of the bilsteen/eibach dampers and springs, so after fitting that I think the car will be be mechanically pretty much spot on!

Scott

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Before condeming the engine, certainly do a compression test etc first. I've heard of similar symptoms from a engine after a blast of loud pedal and the cause was a piece of carbon from the piston crown that had wedged itself between the valve seat and face!

Sounds like a good excuse for regular red-line blasts - but only on a fully warmed up engine!

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It's being fully checked at the moment, compression check etc... Still waiting to hear....

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As I said earlier you only need to remove the two retainers on the top of the cam housing to inspect everything. That way you can check the valve clearances if nothing looks damaged (didn't take much inspection on mine to identify that a cam follower had shattered). You will need to buy a new gasket and if nothing else eliminate a lot of potential causes.

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Hopefully it is this, but it sounds awful and garage suspect on listening that it is either crank or Conrod related... But they will strip down etc tomorrow.

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well engine is screwed. Head is fine - but bottom end was apparently bodged badly by a DPO and the crank shaft is cracked through. Apparently there were two sets of bearing shells on top of each other on the main bearing, no thrust washers and the whole thing was silicon sealented together... no-wonder it leaked constanstly... anyway the block is scrap and so is the crank shaft. Oh and manifold is also cracked so hurrah....

So. I need a replacement engine - I going for HC if possible and I will then stick the good head onto the HC bottom end and add a stainless manifold to result in more power...

Can anyone help on the HC engine front? Have tried most places and there is not much out there...

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I would drop by un-arranged just to have a look at the engine. I would ask to see your good head and make sure the broken block is yours. Im sure they are not lifting your leg but i would want to check!

Buddsy

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I know where there's one, sitting waiting for someone to buy it! Let me make a phone call...

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Bibs, if that is possible, that would be brilliantly amazing...

Buddsy, I trust them, but I will be looking at the car on Friday as I am painting the chassis and tidying up the engine bay - I can recognise the engine anyway from various marks - they have also shown it to all of their neighbours, such was their amazement.. and in any case the noise it was making was particularly awful...

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I shall take some photos when I see it... I just hope I can get an engine relatively soon - it seems whenever the weather is good I can't drive the car - I also really want to have it done for July. At least when it is rebuilt it will be far more durable and more powerful without a potential failure hanging over - it seems the block was basically on the verge of self destruction anyway.

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This garage is feeding you horsepoo. If there were two sets of shells, one on top of the other, 1) the engine would not bolt together and 2) it wouldn't turn over, either. What they are telling you is impossible. Be very,very, careful with this set of gentlemen....

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They are reputable lotus specialist - they said that the metal under the bearing was so damaged the gap had essentially been bridged by an extra bearing (at least that is what I think they said - was quite technical) - however I will take pictures on Friday of the engine in bits so everyone can have a look... either way, I continue to look for a HC engine if anyone knows someone selling a good one - there is one on ebay, but have no idea on condition and its done about 85,000 miles - any thoughts on HC engine durability - re-build time or a chance it - also they do have a video on the ad to it running - thoughts?

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